Skeleton horse traps can spawn in any biome where it can rain, including the deep dark and mushroom fields

MC-99980 has never been resolved.

How to reproduce:

1. Create a creative superflat world without structures with the presetminecraft:bedrock,59minecraft:stone,3minecraft:dirt,minecraft:grass_block;minecraft:mushroom_fields

2. Run /setblock 5 1 0 repeating_command_block{TrackOutput:0b,auto:1b,Command:"/weather thunder"} replace, /setblock 5 0 0 repeating_command_block{TrackOutput:0b,auto:1b,Command:"/tp @e[type=minecraft:skeleton_horse] 0 0 0"} replace and /tick rate 2000

3. Wait a few seconds and a skeleton trap will spawn